The invention relates to a signal discriminating method used in the field of detecting intrusions into premises.
The invention concerns the field of detecting intrusions into premises and specifically relates to a method for discriminating between the signals generated by at least one means sensitive to variations in the pressure of a gaseous fluid constituting the atmosphere of these premises.
The invention also relates to means for implementing the method of the invention, as well as to intrusion detecting devices which comprise these means.
The term premises designates any enclosed space capable of containing at least one person, such as a room of a building, a shed, or the passenger compartment of a vehicle.
The technical field of the invention is that of devices for detecting intrusions into premises, of the type that operate by detecting at least one pressure variation in these premises, such as that resulting from the opening of at least one exit of these premises.
More particularly, though not exclusively, the invention is intended as an improvement to the device that is the subject of the Applicant""s patent FR-A-2.696.033.
Detection devices of this type make use of at least one means sensitive to the air pressure of the premises under surveillance, which generates an electrical signal in connection with any pressure variation detected in these premises.
Intrusion detecting devices that operate in this way are sensitive to pressure variations produced in the premises by phenomena outside these premises, such as those resulting from a gust of wind or a displacement of air generated by the passing of a vehicle.
An object of the invention is to provide a method for discriminating between the signals generated by at least one pressure-sensitive means within the scope of detecting intrusions into premises.
To this end, the subject of the invention is a method for discriminating between signals generated by at least one pressure-sensitive means within the scope of detecting intrusions into premises, characterized in that in order to discriminate between the electrical signals:
when the means sensitive to pressure variations generates an electrical signal, the evolution of the amplitude of at least one characteristic of this signal is monitored,
when two successive amplitude variations substantially opposite relative to a median value are detected, the means for informing people is inhibited, whereas
when amplitude variations of a different type are detected, the means for informing people is activated.
The invention also relates to means for implementing the method of the invention as well as intrusion detecting devices which comprise these means.